PARENT SESSION
Poster Session 30: Soil Ecology.
Wednesday, August 4 Presentations from 5:00 PM to 6:30 PM, Exhibit Hall A 1.
Biomass and distribution of fine roots in hardwoods and softwoods across a calcium gradient in northeastern America.
Park, Byung Bae1, Yanai, Ruth1, Fahey, Timothy2, 1 SUNY College of Environmental Science and Forestry, Syracuse, NY, USA2 Cornell University, Itacha, NY, USA
ABSTRACT- The effect of site quality and forest type on the distribution and quantity of fine roots is poorly known. We measured fine root biomass (FRB) at three well studied sites in the northeastern US: Sleepers River, VT; Hubbard Brook, NH; and Cone Pond, NH. These sites are similar in climate and forest types but represent a gradient from high (Sleepers River) to low (Cone Pond) Ca supply. In each of the three sites, we selected softwood and hardwood stands and five measurement locations in each stand. We used root-coring techniques to estimate FRB as a function of soil depth. Four root cores from each measurement location were divided into 5-cm increments. Fine roots <2mm were sorted into live and dead roots in three diameter classes delineated at 0.5 and 1.0 mm. FRB in the hardwood stands was highest where Ca availability was lowest; Cone Pond, Hubbard Brook, and Sleepers River had 737, 629, and 512 g m-2 respectively. There was no such pattern in softwood stands. As expected, FRB in the softwoods was more concentrated on the surface soil (70% of root mass occurred in the 10 cm depth) than in hardwoods (65%), but there is not statistically different (p = 0.64). Surprisingly, roots were distributed more deeply at the high Ca sites. These results suggest that fine root biomass is greatest at sites with low base cation supply, due to nutrient limitation, and roots are distributed more deeply at sites with greater nutrient supply.
Key words: Ca availability, Cone Pond, Fine root biomass, Sleepers River, Hubbard Brook